Abstract: Most scholars believe the existence of starting pressure, thinking of the threshold pressure resulted from the abnormal of fluid boundary zone properties, non-Newtonian fluid and the lagging of oil-gas phase permeability. But the abnormal of fluid boundary layer properties have been proven to be negative by chemical experts; Small part of scholars believe that there is no threshold pressure, and the illusion of starting pressure existing is because of the respond process of rock strain, the limit of experimental instrument accuracy, man-made measurement error, and additional pressure difference caused by reservoir damage, besides, the presence of threshold pressure gradient cannot explain hydrocarbon migration and production pressure differential phenomena, so the exemplified explanation means no start-up pressure. The investigation shows found that, threshold pressure related problems have always been studied, and there is still much work to do. The core of the work is to make clear the connotation of starting pressure.