The principal target of my thesis is to identify the sources of economic growth in YRD zone. A review of YRD post-reform development is conducted. The em­pirical study examines total factor productivity growth, technical progress, effi­ciency change and the scale effect in 16 component cities in YRD. Panel data of 1985-2007 are analyzed by using the stochastic frontier model. The major issues consider as (1) analyzing the source of YRD growth in which productivity growth is decomposed into three components: technical progress, changes in technical efficiency and the scale effect, (2) comparing the productivity and efficiency per­formance among cities and finding the tendency between the results from different parts of TFP growth, and (3) providing the explanation for my estimation and pol­icy implication. YRD’s growth has been mostly input-driven and TFP growth by average 9.5% each year. For sustaining the engine position in China, YRD should take effort to enhance the technology level and introduce in technical innovation from outsides.