A　diffusion-drift　fluid　model　with　local　field　approximation　was　adopted　for　the　calculation　of　discharge　process　in　pure　nitrogen.　The　Boltzmann　equation　was　solved　to　get　the　electron　transport　coefficients　and　rate　coefficient.　The　negative　and　positive　nitrogen　streamer　at　300K　between　5mm　gap　plate-plate　electrodes　were　simulated.　The　positive　streamer　needs　lower　electric　field　and　longer　time　to　form　the　discharge　channel　than　the　negative　streamer.　The　influence　of　pressures　on　breakdown　electric　field　was　researched.　The　reduced　breakdown　electric　field　decreases　with　the　pressure＇s　increasing.　The　calculated　results　are　consistent　with　the　experiment　results.　©　2019　IEEE.