The methods we proposed is the Dot-Filter and Region growing for the detection of solitary pulmonary nodules. Firstly, Two-dimensional dot-filter is constructed by using Two-dimensional Hessian matrix, and is used to detect the solitary pulmonary nodules. For the CT values of the vessels and airway do not conform to Gauss distribution, lots of normality treated as nodules will emerge after the way used above. Finally, we use Region growing and Tree-dimensional Hessian matrix to eliminate the false-positive. It is a method with high speed and high accuracy.