The invention relates to a preparation and application method of a solid phase extractant capable of simultaneously accumulating multiple heavy metal ions. Firstly, 2.5g of carboxylation carbon nano tube and 30 mL of anhydrous thionyl chloride react for 1-2 days at the temperature of 60-90 DEG C; pump filtration is carried out; after being cleaned, filter residue is dried in vacuum for the whole night to obtain an acylation carbon nano tube; the acylation carbon nano tube is dispersed in a solution composed of 1g of thiosemicarbazide and 100 mL of anhydrous N, N-dimethyl formamide; the mixture reacts under the protection of nitrogen with the temperature of 100 DEG C for 48 hours; pump filtration is carried out; after being cleaned, the filter residue is dried in vacuum for 1-2 days to obtain the solid phase extractant capable of simultaneously accumulating multiple heavy metal ions. The solid phase extractant serves as a column filler to dynamically accumulate 0.5-1 L of water samplesto be detected, wherein the heavy metal ion content of the water samples is 1-5 mu g/L; and the solid phase extractant in which the heavy metal ions are accumulated is eluted and desorbed by utilizing dilute nitric acid, wherein the recovery rate is above 95%, and the desorbed solid phase extractant is repeatedly recycled for 2-3 times. The invention has high efficiency, is simple and can simultaneously accumulate various heavy metal ions, i.e. Cu (II), Ni (II), Zn (II), Cd (II) and Pb (II).