To settle the overshoot and undershoot problem of constructed envelops during the decomposition of strong nonstationary vibration signals by empirical mode decomposition (EMD), a composite interpolation envelope empirical mode decomposition (CIEEMD)method was proposed. Basing on the definition of signal nonstationary coefficients and the method of envelop endpoint connection, a composite interpolation envelope method was formed to improve the accuracy of EMD, in which monotonic piecewise cubic hermite interpolation method was usedto construct local nonstationary signal envelopsand cubic spline interpolation was used to construct local smooth signal envelops. The comparative analysis of simulated signals verified the effectiveness of CIEEMD for nonstationary signals. The CIEEMD was used to diagnose the vibration signals of oversized clearance fault in reciprocating compressor bearing.The results show that the proposed method not only has an excellent decomposition performance, but also gives a more significant fault frequency in envelope spectrum.