Research Conclusions: According to the concept of deformation control and on the basis of the evaluation and analysis of stability of slope weak foundation by adopting safety coefficient method, the factors of deformation features of slope weak foundation should be taken into consideration fully and the sampling safety coefficient for stabilizing embankment should be increased rationally in order to make slope weak foundation having the same stable level as that of lateral weak foundation. When filling embankment is conducted on slope weak foundation, the compressibility of soil of foundation and the bottom transverse slope should be inspected clearly and some measures should be taken for limiting the lateral deformation of slope weak foundation in order to guarantee the stability of slope weak foundation.