Transform parameter derivation based on block partition is described. In an exemplary aspect, a method for video processing includes determining, for a conversion between a first block of video and a bitstream representation of the first block of video, whether a use of non-power-of-two partition trees (NPT-T) is enabled or disabled, wherein the NPT-T includes splitting the first block to multiple smaller sized child blocks of the first block, and at least one child block's width and/or height have a dimension that is a non-power-of-two integer; and performing the conversion based on the NPT-T in response to the determination that the NPT-T is enabled.