After five years implementation of western development, the scale and structure of financial expenditure in western regions changed a lot. According to comparison and analysis of the effect of financial expenditure scale and structure change of western development on economic and social development in west regions, the results show that central government increases financial support to west regions from the angle of financial scale, so as to have obviously increased local financial expenditure in west regions and that the absolute amount of the expenditure in infrastructure, scientific and technological investment, cultural and educational expenditure and administration increased from the angle of expenditure structure and that the expenditure rate is declining. On the one hand, the change of financial expenditure structure promotes regional economic development and people's living level. On the other hand, the change of the expenditure deepens the unfairness of the society. Based on the above analysis, this paper analyzes the changing trends of the financial expenditure in the western regions in the future.