The invention discloses a suspension type triangular frame scaffold and a formwork construction technique thereof. The suspension type triangular frame scaffold comprises a triangular frame vertical support, oblique supports, horizontal supports, formwork correction and alignment screws, hanging frames and rail assemblies mounted at the top of the scaffold. All the structures are spliced together to form an upper formwork, a middle formwork and a lower formwork are formed. A construction scaffold and the formworks are hung on a formed concrete cylinder wall (bottom section concrete) through the formwork correction and alignment screws, namely all loads on a construction platform are transmitted to formed middle concrete and the bottom section concrete through opposite-pull screws; the suspension type triangular frame scaffold is attached to the formworks with the upper layer of the triangular frame scaffold as an operating platform, so that the construction platform is formed; and operation for the upper layer, the middle layer and the lower layer is conducted cyclically till the whole cylinder wall is completed. The construction method is simple, construction equipment can be used repeatedly, the cost is low, and the construction efficiency is high.