This research was aimed to present Technical loss analysis in Hatyai of Provincial Electricity Authority (PEA). This Analysis used calculation and PSS/Adept program. For considering the technical loss in distribution system included: transmission line losses, power transformer losses, distribution line losses and low-voltage transformer and distribution line losses. The evaluation will be compared technical loss both 4 parts and compared technical loss from calculation and measurement which data included technical loss and technical loss. From this research found that low-voltage transformer and distribution line losses have maximum value at 78.72% and technical loss was at 3.33. So in controlling or decrease technical loss have to select appropriate and correctly method by must investigate both cost and most worthily.