The invention discloses a processing technology of a bent aluminium tube water-cooling die-casting cavity. The processing technology comprises the following steps: S1, selecting tubes; S2, annealing the selected aluminium tubes; S3, bending the aluminium tubes; S4, welding the aluminium tubes to water faucets; S5, reinforcing the aluminium tubes; S6, after finish of the S5, placing the bent aluminium tubes into a die-casting mould and positioning the bent aluminium tubes by a positioning device in the die-casting mould; S7, performing mould assembly die-casting: after mould assembly of the die-casting mould, pouring an aluminium alloy solution into a melting cup of a die-casting machine, squeezing and injecting the aluminium alloy solution into the mould through the squeezing and injecting force of the die-casting machine, and enabling the aluminium alloy solution to wrap the aluminium tubes; S8, opening the mould and taking out a casting: after squeezing and injecting, under the pressure-boosting action, enabling aluminium alloy and the aluminium tubes to be closely combined into a whole, keeping the pressure of the casting for 10-15 s, opening the mould and taking out the casting; S9, deburring, and performing local CNC processing to obtain the bent aluminium tube water-cooling die-casting cavity. The processing technology has the benefits that the raw material cost is low, the aluminium tubes are prevented from being molten or deformed in the mould assembly die-casting process, the processing cost is low, the processing period is short and the heat radiating efficiency is high.