Gaussian-modulated coherent state quantum key distribution is gradually moving towards practical application. Gen-erally, the involved scheme is based on the binary random basis choice. To improve the performance and security, we present a scheme based on a continuous random basis choice. The results show that our scheme obviously improves the performance, such as the secure communication distance. Our scheme avoids comparing the measurement basis and dis-carding the key bits, and it can be easily implemented with current technology. Moreover, the imperfection of the basis choice can be well removed by the known phase compensation algorithm.