A multi-arm polyethylene glycol (I) having different kinds of reactive groups and the uses thereof are disclosed, which is formed by polymerizing ethylene oxide with oligo-pentaerythritol as an initiator, wherein, PEG is same or different and is —(CH2CH2O)m-, the average value of m is an integer of 2-250; l is an integer of 1 or more. The method for producing the multi-arm polyethylene glycol having different kinds of reactive groups, the multi-arm polyethylene glycol active derivatives comprising linking groups X attached to PEG and terminal reactive groups F attached to X, the gels formed by the multi-arm polyethylene glycol active derivatives, the drug conjugates formed by the multi-arm polyethylene glycol active derivatives and drug molecules, and the uses thereof in preparing drugs are also disclosed.