This study was carried out to analyze the performance of solar collecting system using the parabolic trough concentrator (PTC) depending on the elements affecting on the system efficiency. The material of solar absorbing tube, an amount of flow rate circulating the solar collecting system, and installation of polycarbonate tube (PC) outside solar absorbing tube were selected as the elements affecting on the efficiency of the PTC solar system. The stainless steel tube as solar absorbing tube presented the most effective performance of solar collecting system in comparing with galvanized tube and copper tube. Flow rate of 18ℓ/min circulating inside the solar absorbing tube of PTC solar system showed the better performance than flow rates of 9ℓ/min and 13.5ℓ /min. The installation of PC (Polycarbonate) tube outside the solar absorbing tube had great effects on the performance of the PTC solar system.