A theoretical and practical study was conducted for the vacuum solar dryer, which locally manufactured to drying of salted and unsalted carp Fish and compared with natural sun drying and vacuum electric dryer in Basrah province for the period from October 2011 to July 2012. The study included simplifying the Crank's equation to predict the theory moisture content compared with practical data. Solar radiation intensity, temperature in the atmosphere and in the solar dried were measured. The results indicated a convergence is too big between the theoretical and practical moisture content and coefficient of determination ranged between 0.8848-0.9503. The average temperature in the solar dryer 50°C in all days of the year with sunny weather while on cloudy days, the temperature in the solar dryer reached to 43°C with fluctuations in solar radiation intensity. The moisture content results of dried Fish by vacuum solar dryer and vacuum electric dryer were convergent but it is significantly better than natural sun-drying method.