The present invention relates to a compound represented by a formula (I), antitumor applications and intermediates thereof, and applications of the intermediates, wherein the intermediates are compounds represented by a formula (III) and a formula (IV), the compound represented by the formula (I) has degradation effects on specific target proteins, and mainly comprises three parts, the first partis small molecules binding protein (SMBP), the second part is a link unit (Linker), the third part ubiquitin ligase binding moiety (ULM) is a ligand with ubiquitination function, SMBP and LIN are covalently bound, and LIN is covalently bound to ULM. According to the present invention, a series of the designed and synthesized compounds of the present disclosure have wide pharmacological activities,have function of degradation of specific proteins and / or inhibition of activities, and can be used for related tumor treatment.