A transform and inverse transform circuit is provided. The transform and inverse transform circuit includes: at least one quantization and inverse quantization circuit, including at least one quantization and inverse quantization unit, wherein each quantization and inverse quantization unit includes a plurality of first coefficients, and each quantization and inverse quantization unit performs quantization or inverse quantization on one of multiple ways of inputting data; and at least one one-dimensional transform circuit, coupled to the quantization and inverse quantization circuit, wherein the one-dimensional transform circuit includes a plurality of second coefficients, wherein the one-dimensional transform circuit performs one-dimensional transform on the inputting data processed by the quantization and inverse quantization circuit, wherein the plurality of first coefficients and the plurality of second coefficients are set up based on a video codec standard.