A method of laser continuous scanning Doppler testing based on sub region division and mode reconstruction is proposed to measure the operational deformation shape of flat plate structure with arbitrary circular holes. Firstly， the surface of a flat plate structure with arbitrary circular holes is divided into several sub regions， which are completely covered by rectangular and circular scanning. The operational deformation shape of each sub region is obtained by using constant speed linear continuous scanning and spiral scanning methods respectively. Then， considering the problems of amplitude ratio， different reference plane and rotation angle， and reverse vibration on both sides of the pitch diameter， the operational deformation shape of all sub regions is spliced and reconstructed to obtain the operational deformation shape of the whole structure. Finally， compared with the simulation results， measured modal assurance criterion （MAC） values are greater than 0.95， verifying the effectiveness of the method. This method can realize the continuous scanning laser vibration test of flat plate structure with arbitrary circular holes， and thus has the advantages of high efficiency and dense measuring points. It plays an important role in further improving the application scope of its engineering applications.