The invention relates to an SCMA codebook design method based on the maximization sum distance of constellation points. The method comprises the following steps of: firstly, maximizing the sum distance among projection points of a rotated QPSK constellation on a coordinate axis, selecting an optimal rotation angle represented by a formula as shown in the specification, and taking the QPSK constellation having the rotation angle represented by a formula as shown in the specification as a mother constellation C+ after normalization processing; then, respectively rotating the projection of the mother constellation C+ on an X axis in alpha, beta and gamma, and constructing a constellation diagram that three users are stacked on a single resource block; on the premise that alpha is kept constant, maximizing a sum distance function f(alpha, beta, gamma) among the constellation points of the three users stacked on the single resource block so as to obtain optimized rotation angles beta and gamma; and finally, designing an operation factor matrix delta<j> according to alpha and the corresponding optimized angles beta and gamma, and furthermore, in combination with a mapping matrix V<j>, mapping the two-dimensional mother constellation C+ to obtain codebooks U<j> of six users, wherein j is 1, 2, ..., 6. According to the method disclosed by the invention, the sum distance among four constellation points of each user and the sum distance among the constellation points of three users stacked on each resource block are respectively maximized through optimal calculation for two times; and thus, the bit error rate performance of the system is improved.