A method for quantitative determination of fish sperm deoxyribonucleic acid (fsDNA) in solutions was developed by using adsorption preconcentration and near-infrared diffuse reflectance spectroscopy (NIRDRS). A high capacity adsorbent of amino-modified silica particle (AMSP) was prepared for preconcentration of fsDNA in solutions. Under the optimized conditions, the adsorption rate can be above 90% within 3 min. After adsorbing the DNA onto the adsorbent, near-infrared (NIR) spectra in diffuse reflectance mode were measured and partial least squares (PLS) model was established for fast quantitative prediction. The results show that the correlation coefficient (R) between the predicted and the reference concentration is 0.9894 and the recoveries are in the range of 92.9-123.4% for the validation samples in the concentration range of 3.00-29.38 mg L(-1). Therefore, the feasibility for quantitative analysis of DNA in solutions by NIRDRS is proved. This may provide an alternative way for fast determination of DNA in solutions.