质量导致时空弯曲但这不是这里要说的。See wiki in GR explaining that GR is to replace gravitational force by spacetime geometry:

General relativity is a metric theory of gravitation. For this class of theory, the main defining feature is the concept of gravitational 'force' being replaced by spacetime geometry. Phenomena that in classical mechanics are ascribed to the action of the force of gravity (such as free-fall, orbital motion, and spacecraft trajectories) are taken in general relativity to represent inertial motion within a curved geometry of spacetime