This paper illustrates the scientific base of the ecological civilization and the connotation of its engineering,which understanding the ecological carrying capacity is the core of the ecological civilization construction, like civil engineering relying on the base. This paper proposes the index system of the regional ecological carrying capacity pointing that the new ecological engineering is to adapt to the ecological carrying capacity and the four-ecology principle of the ecological engineering using the Guilin region's water conservancy project as an example. This paper also points out that the new town is an artificial ecosystem that superimposes on the regional natural ecosystem,so the large-scale constructions of new towns should follow the principles of the ecological engineering.