Recently, cold-formed steel (CFS) has become a popular material for low- and medium-rise building structural elements. Where the CFS section assembles the beam and column parts. The merits of CFS might make the construction lighter and more effective to field modifications. In regions prone to earthquakes, the structure's mass is crucial. The combination of CFS and lightweight concrete is proposed to reduce the structure's weight and reduce the seismic activity of the building. This paper investigates the parametric behavior of beam-to-column composite connection using the CFS section, where the slab component is a lightweight concrete material. The CFS was constructed using a double-lipped channel (DLC) section that was arranged in a back-to-back arrangement. In contrast, the beam is made of DLC250 and the column is built of DLC300. In this research, a 5 mm gusset plate with a haunched gusset plate structure was presented. The isolated joint test of lightweight concrete (IJLW) with parametric method is carried out based on the Eurocode Standard to calculate the connection moment resistance, connection stiffness, and connection classification. According to the results of the parametric calculation, the connection's moment resistance was 67.28 kNm, and its stiffness was 1464.39 kNm/rad. The failure mode shows that the connection fails at beam bolt hole in bearing. The results show that the connection is classified as semi-rigid, partial strength, and ductile behavior.