拖拉机工作时，其发动机转矩、驱动轮转矩、动力输出轴转矩、旋耕转矩、悬挂销或牵引杆上的作用力等都是随机载荷或含有随机成分,以恰当的函数来描述这些载荷信号的功率谱特性对于分析拖拉机系统的动态性能和动态过程仿真是至关重要的，本文推荐了一种功率谱函数的普遍形式并对其性态作了分析，并给出了拟合实例，证明这种函数具有较强的适应性。 Tractor work, its engine torque, drive wheel torque, PTO shaft torque, rotary torque, hanging pin or traction rod on the force are random loads or contain random components, to describe the appropriate function The power spectral characteristics of these load signals are crucial for the analysis of dynamic performance and dynamic process simulation of tractor system. In this paper, a universal form of power spectrum function is proposed and its behavior is analyzed. Examples, prove that this function has strong adaptability.