The self-mixing interference based on a Vertical-cavity Surface-Emitting Laser(VCSEL) was investigated. By taking a VCSEL as the source of a self-mixing interferometric system, the effect of different types of scattering surfaces and injection currents on the self-mixing signals was analyzed. It is concluded that the black and glossy photographic paper target will bring unfavorable influence on the self-mixing velocimeter and the operating currents with 1-1.4 times of the threshold currents can offer a self-mixing signal with a stable and great amplitude. For the longer preheating time, the power-up time of self-mixing velocimeter was discussed, and the results show that Doppler frequency will be stable and accurate after 17 s. The obtained results provide instructions for the parameter optimization and the choice of light source of a self-mixing velocimeter using the VCSEL.