The feasibility of utilizing near infrared spectroscopy for estimating frozen and thawed white croaker surimi with different grades was presented in the research.First-derivative and standard normal variable transformation were used as pretreatment method,then principal component analysis was carried out on the processed datas.Establish grade estimation model on white croaker surimi with different grades by principal component analysis-mahalanobis distance pattern recognition method.Seven kinds of physicochemical indexes(moisture,protein,crude fat,salt-soluble protein,gel strength,water-holding ability and whiteness) of white croaker surimi with different grades were determinated.We came to the following conclusions.Firstly,white croaker surimi with three grade could be distinguished effectively by principal component analysis.Secondly,the model of grade estimation established by principal component analysis-mahalanobis distance pattern recognition method had better performance on frozen white croaker surimi than thawed ones,the former’s comprehensive accuracy was 96.3% with the latter’s is 83.3%.Thirdly,the physicochemical indexes of white croaker surimi with different grades had some distinctions.The research indicated that near infrared spectroscopy could estimate the grade of white croaker surimi rapidly and nondestructively.