The invention discloses a device for concentrating an extracting solution during organic phosphorus analysis in deposit sediments. The device consists of a sample cold drying pipe, a cold drying pipe fixing device and a common refrigerated centrifuge and is simple in structure and convenient to operate. Because the sample cold drying pipe is used, a film covers an opening of the cold drying pipe, and a cold drying hole is formed in a pipe cover of the cold drying pipe, water is lost instead of solute in the process of performing freeze drying on a pre-frozen product. The cold drying pipe in the invention is small in volume (properly 50 ml), multiple samples can be treated by the fixing device every time, and the device is suitable for concentration analysis of lots of samples. The device is simple in structure and easy to operate, analysis of samples in batches can be performed, and the problem that the extracting solution cannot be concentrated during organic phosphorus analysis in deposit sediments in rivers and lakes is solved.