In order to greatly enhance the algorithm performing efficiency, a new encoding scheme was developed. Groups were represented by their own group number, and the molecular structure was described by string figures. 采用基团的子基团号组合直接表示分子的新编码方案,生成的分子形式简单,且基团的各种参数均通过子基团号链接,大大增加了算法的执行效率。