Fruits are usually graded according to their quality. The purpose of the grading is to grad fruit into uniform categories (according to size, shape, weight, color and ripening stage). So fruit can be classified to different grades according to the requirements of the market. Due to the lack of the small grading machinery for small farms and the high prices of large grading machinery, this study aimed to designing, manufacturing and performance evaluating of a prototype for orange grading based on the dimensions of the fruit, which take place without physical contact. The prototype uses different successively operating components, such as phototransistors and actuators, each performing a specific task. The operating principle depend on the phototransistor, signal gathering circuit a processing circuit and output circuit for distributing unit. When it works, the system receives digital signals produced by fruits that shadow the light from a phototransistor sensor during fruit measuring. These digital signals processed by an electronic circuit and the fruit's sizing level are deduced. Then, the system will output switch signals to open the sorting switches according to fruits' size. Testing of the grading prototype results was statistically factorial in completely randomized design, featuring three control factors (conveyor chain velocity, sphericity percentage of fruit and stopping time) and three performance evaluation parameters (grading efficiency, damage percentage and productivity). The result showed that the best degree of grading efficiency obtained with the best degree of damage percentage were at 0.15m/s chain velocity and 1.5 sec Stopping time. The best obtained values of grading efficiency were (92.2%) with (7.1%) damage fruit. The energy required was 160.2 Watt/h. The cost of materials and manufacturing of the final grading prototype was 10000 L.E. The cost of grading prototype per hour was (4.918 L.E).