Abstract: Based on the refined interpretation of over 200 seismic profiles in Bohai Bay basin, the tectonic styles developed in the basin and the tectonics and movement times they reflect are systematically analyzed. Tension, compression, strike slip and superimposition are four major tectonic styles developed in this area. The correlation of sequence and structural layers related with the tectonic styles indicates that during the Palaeozoic this area experienced two stages of compression, two stages of tension or strike slip motion and two stages of tectonic inversion. The balanced cross section analysis for 20 seismic profiles throughout the area shows, although different structural tracts experienced different tectonic activities, their total mechanical characters, development times and tectonic styles are consistent. Generally speaking, it is mainly expressed in: compression in T3, relatively stable in J1+2, tension in J3+K1, compression in K2, and tension in E-Q. The diverse evolutions in different tracts during the Meso-Cenozoic time controlled the Palaeozoic remains and burial. An analysis on the Palaeozoic original reservoirs indicates that for the superimposed basin having experienced polyphase tectonic disturbance reconstruction, one of the key factors for oil and gas accumulation is whether the Palaeozoic strata can produce hydrocarbon again or not at a later time. Therefore, the inversion tectonic transition zone with effective Palaeozoic hydrocarbon source sequences, and with shallow burial or weak denudation during the Mesozoic and deep burial during the Cenozoic, is favorable for accumulations of the Palaeozoic original reservoirs.