The inefficiency that occurs during the slicing step of rapid prototyping based on STL models is addressed using an improved slicing algorithm. Using a hash table, the method builds the integral topology of STL models beforehand. This enables direct acquisition of con-tours. Then, by creating the slicing relation matrix, the method reduces the search range in slicing, potentially saving a substantial amount of time. The demos indicate that the method's temporal complexity is approximately linear. Through application examples, the effectiveness and efficiency of the methodology have been demonstrated, and the results show that it outperforms other existing methods, especially when the STL model is large or complex.