This paper introduces a garbage collection algorithm which is applied to embedded java virtual machine. The algorithm improves generational GC (Garbage Collection) algorithm in the division of generation and the way of collecting old generation, to make full use of the heap and shorten the pause time that dues to full recycling, and make it more suitable for embedded devices where high real-time property required. Experimental results show that the algorithm can improve the real-time property of the system on the basis of maintaining a high efficiency.