Abstract: This paper estimates Chinas economic uncertainty index at the national level and of 31 provinces （cities and regions），and analyzes the impact of economic uncertainty on business cycle fluctuations and the effectiveness of fiscal policy The research findings are as follows：（1） economic uncertainty at the national level and economic uncertainty at the provincial level are both important factors affecting the fluctuation of provincial business cycle；（2） during periods of higher economic uncertainty，fiscal policy has a higher multiplier effect and can serve as a policy tool to compensate for the weakening of monetary policy effects；（3） enhancing market confidence and easing credit constraints are important ways for fiscal policies to exert the “stabilizing growth” effect，and fiscal policies mainly affect economic growth through investment channels Therefore，proactive fiscal policies are an effective tool for addressing the impact of uncertainty

Key words: economic uncertainty, fiscal policy effectiveness, market confidence, credit constraints

摘要： 本文估算了中国国家层面和31个省（市、区）的经济不确定性指数，并分析经济不确定性对经济周期波动和财政政策有效性的影响。研究发现：（1）国家层面和省级层面的经济不确定性都是影响省级经济周期波动的重要因素；（2）在经济不确定性较高的时期，财政政策具有更高的乘数效应，可以作为弥补货币政策效应减弱的政策手段；（3）增强市场信心和缓解信贷约束是财政政策发挥“稳增长”效应的重要途径，且财政政策主要通过投资渠道影响经济增长。因此，积极有为的财政政策是应对不确定性冲击的有效工具。

关键词: 经济不确定性, 财政政策有效性, 市场信心, 信贷约束