To obtain stable solution flow is very important to biological cell micro injection; this paper adopts the method of computational fluid dynamics, unsteady flow dynamic characteristics of the conical micro channel initial flow were researched. The independence of the model grid was verified; the error between exit speed and the theoretical value is within 5%. Established the micro channel gas-liquid two phase unsteady flow model, under different inlet pressure, flux and flow resistance characteristics of the solution in the conical micro channel were studied. Through the study found that flux is fluctuation in the initial period of the micro channel flow, under the minimum inlet pressure that can flow, except the time liquid film flow fluctuation broken, flow tends to be stable within the entire circulation time, and the flow is very small. With the increase of inlet pressure, micro channel flow increasing, within flow time flux volatility increases, and the greater the inlet pressure, the earlier the volatility moments. Micro channel flow resistance change over time, the smaller the inlet pressure, the greater the resistance and the instantaneous maximum flow resistance after flow stability. The results show that Choose inlet pressure slightly higher than the critical flow pressure can get good liquidity; flow is stable and easy to control. The study provides reference for the research of biological micro fluid injection.