This work introduces and discusses the issues of several common startup techniques for boost dc-dc converters. Moreover, basic operating principle of boost converters and three kinds of startup techniques will be briefly introduced in this work, and then an improved method is presented. The mathematical models of two chosen startup methods are built, and MATLAB simulation is used for comparison. In this work, the goal of the startup technique for boost dc-dc converters is to successfully start up the converter at a low input voltage, while effectively limiting the in-rush current at high input voltages.