An adjustable contour and slope practice putting green assembly having a base (22) and a practice putting green platform (21) mounted to the base for support of the platform (21) and a player standing on a support area (28) of the platform (21) over the base (22). The base (22) is formed for selective tilting of the platform (21). The weight of a player standing on the putting green platform (21) is used to hold or fix the platform (21) to the base (22) in an adjusted position. The platform (21) is cantilevered away from the base (22) and preferably the base assembly (22) includes a spherical surface structure (34,51) and a ring (23) cooperatively formed to enable universal adjustment of the slope of the platform (21) about the center of a spherical surface (34,51) when the player is not standing on the platform. The platform may be deformable, for example, by including a deformable peripheral frame (42) which enables adjustment of the contour of the playing surface (29) in addition to adjustments to the slope of the surface (29). The contour adjustment is independent of the slope adjustment. A method of using an adjustable slope, contour and length practice putting green assembly also is provided.