The invention discloses an adaptive detection method for a distance expanded object based on a variable-element generalized structure, belongs to the field of radar signal processing. Aimed at solving the problem that a covariance matrix estimation method and an adaptive distance expansion detector are hard to adapt to a transitional clutter environment, clutter non-Gaussian characteristic information is utilized reasonably, a unified covariance matrix fusion estimation framework is constructed, an adaptive detector of the distance expanded object is constructed in a product fusion form on the basis of general characteristics of detection statistics of present optimal distance expanded objects in the specific clutter environment, a single parameter is utilized to realize design of the detector for the distance expanded object in the transitional clutter environment as well as synchronous control of the corresponding clutter covariance matrix estimation method, the detector structure matches the corresponding clutter covariance matrix estimation method, parameters are set in a concise manner, the detection performance of a broadband radar in the complex clutter environment is improved effectively, and the popularization and application values are high.