Using laser measurement method for the helicopter blade pyramid angle detection has the advantages in simple structure, fast respond and high accuracy. The detecting principle and the realization of the helicopter pyramid angle based on the laser cutting method are introduced. Compared with previous measurements, design a new laser light path structure by using spectroscopes. Based on similarity criterion, the calculation methods on some critical components parameters of the helicopter dynamic balance test platform model are introduced. By simulation experiment the system can fully meet the design requirements and runs steadily.