The invention relates to a method of designing controllers of a VSC-HVDC system based on Clark transform. The method is characterized by comprising the following steps: getting a phase differential model under an ABC coordinate system according to the Kirchhoff's law; getting a mean model under the ABC coordinate system according to the phase differential model under the ABC coordinate system; getting a mean model under an Alpha-Beta coordinate system through Clark transform according to the mean model under the ABC coordinate system; getting a small signal model under the Alpha-Beta coordinate system according to the mean model under the Alpha-Beta coordinate system; and designing an inner loop controller, an outer loop active power controller and an outer loop DC voltage controller of a VSC-HVDC system according to the small signal model under the Alpha-Beta coordinate system. The method has the advantages of being scientific and reasonable, stable in operation, highly precise, good in control effect, highly applicable, and the like.