Abstract: Ningbo has accumulated a series of new technical achievements during the last two rounds of urban rail transit construction, of which quasi-rectangular shield technique can be deemed as a representative, providing line designers with new perspectives to solve engineering problems. Optimized practice carried out by the designers with this technique in main line designing, access line designing and parking line designing is discussed with emphasis. Practice indicates that, by using the quasi-rectangular shield technique, design scheme can be optimized, and coordination and implementation difficulties can also be abated, well controlling project investment.