This study was mainly conducted to fabricate and evaluate a harvester unit for onion crop. So the experimental design was implemented with four different of blade types, tilt angle of shares and speed ratio under three different harvesting depths. These variables were tested according to Total losses concerning(Blade damage - Brushing damage - Conveying losses - Un-lifted bulbs ratio); Efficiencies concerning(Digging efficiency - Cleaning efficiency - Harvesting efficiency - Field efficiency); Effective field capacity; Specific energy and Total costs. All trials were preceded in El-Serw Agic. Res. Station, Damietta Governorate during the onion harvest season 2020-2021. The overall results were summarized into the modification in the onion harvester with blades changed to scoop shapes with tilt angle of shares of 25⁰ and speed ratio of 2.11 under harvesting depth of 11 cm to achieve the lowest total damage and high efficiencies and specific energy with less overall costs in general. While some parameters showed the best results in partial variables as gator blades and 5 cm digging depth for effective field capacity and field efficiency; speed ratio of 1.7 for effective field capacity, cleaning efficiency and specific energy and blade angle of 20⁰ for field efficiency.