Protein isolation from beans is commonly carried out to increase protein availability and digestibility. Protein isolates made through the spray drying process have functional properties and characteristics. The variation of spray drying inlet air temperatures affects the properties of jack bean tempeh protein isolate (JTPI). The protein of jack bean tempeh was extracted and isolated using the method of the isoelectric point approach. The isoelectric point of jack bean tempeh was determined at a pH of 4.20 using the turbidimetry method. The research aimed to identify different inlet spray drying air temperatures on the physical characteristics and functional properties of JTPI. The spray drying method of JTPI was carried out using variations in inlet temperatures were 140°C, 150°C, and 160°C, and then moisture content, protein content, water holding capacity (WHC), and microstructure by Scanning Electron Microscopy were determined. The results showed that the 150°C inlet air temperature variation gave the lowest value for JTPI moisture content (3,91±0.04%). In comparison, the 160°C inlet air temperature variation gave the highest value for JTPI protein content (49.6±0, 30%) and JTPI water holding capacity (3.89±0.03 ml/g). The microstructure of JTPI obtained was porous, with a more spherical shape found at lower inlet temperature but wrinkled at the higher inlet temperature. The inlet temperature also affects the particle size JTPI. The inlet temperature of 160°C can be carried out to produce JTPI, which requires both high protein content and water holding capacity.