Abstract: In response to the static voltage stability problem of multi-energy coupling system, this paper proposed the static voltage stability analysis method for electric-gas-heat integrated energy system（IES）. First, each energy carrier and coupling equipment in the IES are modeled and unified solved to obtain the unified Jacobian matrix J. Then, the reduced matrixes Jr, JR for static voltage stability analysis of IES are derived. Jr considers the effect of multi-energy flow state variables on the reactive power, the physical meaning clear and its computational complexity is small. JR further considers the influence of the multi-energy flow control variables on voltage, which has less conservative, but the calculation is relatively complex. On this basis, this paper discussed the static voltage stability index based on singular value decomposition of J and Jr, JR, and explored the influence of energy carriers’ load fluctuation on the index of IES and grid voltage stability. Verification by numerical examples, the index contains important margin information about voltage stability of IES, and the reduced matrixes proposed in this paper can better describe the static voltage stability problem in IES.