Suspension is all connected devices collectively force transmission between the car frame and axles, its function is the road reaction force acting on the wheel on the vertical longitudinal reaction force and lateral reaction force and the reaction force caused by these moments are To pass to the frame in order to ensure the normal running of the car. Automotive suspension generally consists of elastic components, shock absorbers and guiding mechanism composed of three parts, which are divided into non-independent suspension and independent suspension into two categories [2]. Non-elastic element can be divided into independent suspension leaf springs, coil springs, air springs, and gas springs, spiral springs, air springs, the need for more complex oil and gas springs guiding mechanism. While using leaf springs, leaf springs because the act itself and the guide mechanism, and a certain damping effect, thus making the suspension structure greatly simplified, so the current car trailer commonly used non-independent suspension and leaf spring with integral I-shaped cross-section axle [3]. Suspension is all connected devices collectively force transmission between the car frame and axles, its function is the road reaction force acting on the wheel on the vertical longitudinal reaction force and lateral reaction force and the reaction force caused by these moments are To pass to the frame in order to ensure the normal running of the car. Automotive suspension generally consists of elastic components, shock absorbers and guiding mechanism composed of three parts, which are divided into non-independent suspension and independent suspension into two categories [2]. Non-elastic element can be divided into independent suspension leaf springs, coil springs, air springs, and gas springs, spiral springs, air springs, the need for more complex oil and gas springs guiding mechanism. While using leaf springs, leaf springs because the act itself and the guide mechanism, and a certain damping effect, thus making the suspension structure greatly simplified, so the current car trailer commonly used non-independent suspension and leaf spring with integral I-shaped cross-section axle [3]. American suspension parameters: Model Traction Suspension Seat height (MM) A1 (MM) B1 (MM) A2 (MM) B2 (MM) A3 (MM) B3 (MM) H (MM) carrying capacity ZYXJ03-110 1110 399 369 390 360 381 351 115 16,000 * 3 ZYXJ03-130 1130 419 389 410 380 401 371 135 16,000 * 3 ZYXJ03-150 1150 439 409 430 400 421 391 155 16,000 * 3 ZYXJ03-180 1180 469 439 460 430 451 421 185 16,000 * 3 ZYXJ03 -210 1210 499 469 490 460 481 451 215 16,000 * 3 ZYXJ03-230 1230 519 489 510 480 501 471 235 16,000 * 3 ZYXJ03-250 1250 539 509 530 500 521 491 255 16,000 * 3 ZYXJ03-270 1270 559 529 550 520 541 511 275 16,000 * 3 ZYXJ03-300 1300 589 559 580 550 571 541 305 16,000 * 3 ZYXJ03-320 1320 609 579 600 570 591 561 325 16,000 * 3 ZYXJ03-350 1350 639 609 630 600 621 591 355 16,000 * 3 Note: 1. , upon request to select a balance arm pin, 50, 60 or 70 type 2 type, customers need to select the side wall thickness of 6mm, 8mm or 10mm 3, leaf spring width 90mm, 100mm, 120mm optional board reed several to choose from 4, A is the no-load size, B size when fully loaded right to the Company to improve the product according to the specific circumstances to retain specific size to the actual subject