The invention relates to a printable red light emitting polymer and a preparing method thereof.The red light emitting polymer is prepared through ring-opening metathesis polymerization, has a norbornene derivative main chain and has red light iridium complex on a side chain.The soft polymer main chain is beneficial for improving viscosity, film-forming performance and flexibility of the material, the material is more suitable for ink jet printed films, and a large-area soft device can be prepared; the red light iridium complex is beneficial for efficient light emitting, while improving material solubility, solubilizing groups can effectively control mutual action among molecules to control annihilation of the triplet state, and light emitting efficiency is improved.The structural formula of the red light emitting polymer is as follow (see the formula in the description).The material has the advantages of being easy to purify, high in yield and heat stability and good in film-forming performance, and a large-area soft device can be prepared through an ink-jet printing method.