The invention provides an underwater vehicle three-dimensional path planning method based on a Lazy Theta satellite and particle swarm hybrid algorithm. The method comprises the following steps of 1, performing navigation space modeling; 2, building a Lazy Theta satellite algorithm cost function; 3, performing two-dimensional path planning in a horizontal plane by using a z=zsafemin horizontal plane as a Lazy Theta satellite algorithm two-dimensional path plan plane, and using X-axis and Y-axis coordinates (xs, ys) of a path starting point S and X and Y-axis coordinates (xd, yd) of a path terminal point D as a starting point and a terminal point of a two-dimensional path; 4, finding a collision-free length-shortest path optimization target according to three-dimensional path planning; designing a depth plan evaluation function; 5, using a particle swarm algorithm to perform depth planning; 6, outputting an optimum three-dimensional path. Through the simplification on a three-dimensional problem, the advantages of two kinds of different algorithms are combined; the calculation complexity of the algorithm is reduced; the high speed performance and the reliability of the three-dimensional path planning are improved.