研究了光盘机两级道跟踪伺服系统构成的特点。对不测量执行机构两级之间位置的道跟踪伺服系统，给出了一种通过增加耦合，使没有位置传感器的第一级获得等效反馈信息的设计方法，并给出了计算机仿真结果。理论推导和仿真结果表明，对于一般参数范围的系统，所给的设计方法是可行的并使得设计更加简单。 The characteristics of two-track tracking servo system of CD player are studied. For the tracking servo system which does not measure the position between the two actuators, a design method of obtaining the equivalent feedback information by adding the coupling so that the first stage without the position sensor obtains the equivalent feedback information is given and the computer simulation results are given. The theoretical derivation and simulation results show that the design method is feasible and makes the design easier for the system of general parameter range.