The invention provides a three dimensional printing apparatus and a three dimensional printing method. The three dimensional printing apparatus includes a tank, a platform, a curing device, and a controlling device. The tank contains a liquid forming material, an inner bottom of the tank has a first portion and a second portion in step manner, and the first portion is higher than the second portion. The platform is to be immersed in or moved out of the liquid forming material. The curing device is disposed next to the tank or the platform. The controlling device is electrically connected to the tank, the platform and the curing device. The controlling device drives the tank and the platform to rotate relative to each other and to move relatively closer to or further away from each other, so a region of the platform is switchably corresponding to the first portion or the second portion. When the region is corresponding to the first portion, the curing device cures the liquid forming material between the platform and the first portion to form a solidified layer, and then the controlling device rotates the tank and the platform relative to each other to peel off the solidified layer from the first portion and move the solidified layer to a position corresponding to the second portion. The apparatus and the method have the advantages of increasing the printing efficiency and accuracy, extending the scope of printable objects, and increasing structural strength of a printed three dimensional object.