The invention discloses an InSAR unwrapping error detecting method based on an interferogram closed loop. The method comprises the steps of acquiring an SLC image of a researching area, performing a multi-view operation, a filtering operation, an interference smoothing operation, a landform phase eliminating and an unwrapping operation, and obtaining an unwrapped InSAR differential interferogram; selecting a target interference pair, detecting the other two interference pairs which can form a closed loop with the target interference pair, obtaining a plurality of sets of interferogram closed loops, and resolving the residual error of three interference pairs in each set; performing polynomial fitting on an interference pair closed loop residual error which comprises a rail error, and resolving a polynomial parameter by means of a least square method, and resolving a difference between the closed loop residual error and a polynominal fitting result; taking the pixels of which the absolute values are smaller than 0.5*2pi radian in each set of closed difference result, masking other pixels, calculating a union set of each reserved difference interference pair; and calculating an intersection set between a union set result and a target interference pair pixel, and determining the pixels which are masked by the target interference pair as the pixels with unwrapping errors. The InSAR unwarpping error detecting method improves effectiveness and accuracy of a positioning unwrapping error result.