New crystal of cefotetan acid and preparation method thereof

The invention relates to a new crystal of cefotetan acid and a preparation method thereof. The invention provides a new crystal form of [6R-(6a,7alpha)]-7-[[[4-(2-amino-1-carboxyl-2-oxoethylidene)-1,3-dithioheterocyclobutyl -2-yl]carbonyl]amino]-7-methoxy-3-[[(1-methyl-1H-tetrazolyl-5-yl)thio]methyl]-8-oxo-5-thia-1-azabicyclo[4,2,0]octyl-2-ene-2-formic acid. The crystal form has characteristic peaks when the reflection angle 2theta in the X-ray powder diffractogram is 11.66+/-0.1 degrees, 17.53+/-0.1 degrees, 17.72+/-0.1 degrees, 18.91+/-0.1 degrees, 20.01+/-0.1 degrees, 21.02+/-0.1 degrees, 22.24+/-0.1 degrees and 23.33+/-0.1 degrees. The compound crystal form has the advantages of favorable stability, simple preparation technique and lower preparation cost, and can implement industrial production.