The invention provides a self-assembly preparation method of a spherical manganese-lithium silicate composite anode material. A CNT (carbon nano tube) and a manganese-lithium silicate material are compounded, so that the conductivity of manganese-lithium silicate is improved due to the ultrahigh conductivity of the CNT. In the method, spherical manganese-lithium silicate particles are formed by self-assembly of manganese-lithium silicate nano-particles through in-situ preparation by taking the CNT as a crystal nucleus, and the CNT is inserted between spherical secondary particles. The invention also provides an anode composition containing the self-assembly composite anode material of spherical manganese-lithium silicate and the CNT prepared by the preparation method and a lithium ion secondary battery containing the anode composition.