Solid-state nanopores are a powerful tool for DNA molecules detection. Here, we achieve the distinction of single and double strands of short DNA moleculess with silicon nitride nanopores. The experimental results show that the translocation of single-stranded DNA of 22 bases through a silicon nitride nanopore of about 5.5 nm is dominated by electroosmotic flow. However, after binding to a complementary DNA probe to form a double-stranded DNA, the DNA molecules changes its direction of translocation driven by electrophoretic force due to the change of charge density. The results of DNA trans-pore events show that double-stranded DNA caused twice as much current blockage as single-stranded DNA, which makes it possible to achieve single- and double-stranded DNA’s screening by solid-state nanopores which has important implications for rapid disease detection using probes.