i am bit confuse in selecting 16-bit architecture device family. In my project there is need of DSP. so i think dsPIC30 and dsPIC33 will fullfill my requirement.
but i don't know the basic difference between these family.
You are apparently looking for processors with dedicated DSP machine (dsPIC30 and 33). For the more subtile differences between both families, refer to MCHP overwiev documents, online selection tools and detail data sheets. The overview is here **broken link removed**