Sun Guoh-Tyng’s “Shu Pu” is a classic calligraphy copybook to learning cursive script. Most of the cursive script in the text can be compared closely between the regular script and cursive script by means of simplifying, omitting, and connecting strokes. A few cursive scripts that are difficult to correspond to regular scripts must be traced back to seal script, official script and Qin and Han bamboo slips. This study explored the origin and development of cursive script in four categories, including seal and official script, bamboo slips of the Qin and Han dynasties, official script on inscriptions of the Han Dynasty, and variant characters.The research results show that most of the cursive script with weak correspondence between regular script and cursive characters can only be clarified the origin and development by analyzing the configuration of the Qin and Han bamboo slips. This study further found that four cursive methods result in low correspondence between regular script and cursive script, including changing stroke joints, stroke order, recombining characters’ structures, and reusing connection and shortening methods of strokes. To sum up, bamboo slips of the Qin and Han dynasties are an important source of understanding cursive script’s configuration, which deserves to be studied systematically, so that the method of studying the structure of cursive script can be understood reasonably.