The scale and effectiveness of investment activity is mainly associated with the creation of an attractive investment climate in the region, which reflects a combination of factors that allow the investors to safely invest in order to provide the materials, resources and get guaranteed benefits with high material output. Construction has always been distinguished by capital and material consumption, cycle time, the use of special equipment and technologies, as well as a special management system to attract and implement investments. But even with the correct calculations, investments may not bring the expected results due to lack of business and entrepreneurial resources, including those at the regional level. But on the other hand, investment processes in general, and in construction in particular, form the business activity of the region and business entities. The purpose of the study is to clarify the methodology for assessing the investments impact (general and in construction) on the business activity level in the region. The tasks of identifying the level of investments’ influence on the parameters of business activity in the region and conducting testing of the proposed developments on the Crimean region example were solved. As a result, a definition of business activity in the region was developed with the allocation of the regional socio-economic system parameters’ blocks with a justification of the investment activity characteristics, including in construction. An approach to assessing the business activity of the region is proposed, within the framework of which the correlation dependence of the investments influence on the regional business activity level is calculated using the example of the Crimean regional complex. The identified parameters of the investments’ impact flows both in construction, material production, and in innovation, can serve as the basis for developing a set of measures to stimulate the investors regarding the required indicators of the socio-economic development of the territory.