The newest video compression standard, high-efficiency video coding (HEVC), obtains a higher coding efficiency than previous video compression standards, at the expense of a significant increase of computational complexity. To reduce computational complexity, implementation-friendly encoding algorithms that efficiently trade off coding efficiency and complexity should be designed. We address this issue by proposing a fast prediction unit (PU) partition mode selection scheme from the perspective of spatial correlation of visual signal. Motion similarity of spatially neighboring blocks is first introduced into the PU partition mode selection for HEVC, and the concept of motion homogeneous coding unit (CU) is first proposed. For the motion homogeneous CU, a new method is proposed to reduce the number of its candidate PU partition modes to speed up the PU partition mode selection. Experimental results show that the proposed scheme can achieve lower computational complexity than the five state-of-the-art fast methods while maintaining a similar rate distortion performance.