Long non-coding RNAs (lncRNAs) are involved in colorectal cancer (CRC) progression, however the mechanisms remain largely unknown. The present study aimed to reveal the role and possible molecular mechanisms of a new LNCRNA, LINC00858, in CRC. LINC00858 was increased in CRC tumor tissues, and patients with high LINC00858 expression had a shorter survival time. Knockdown of LINC00858 expression suppressed cell proliferation and induced G(0)/G(1) cell cycle arrest and apoptosis in TP53-wild-type CRC cells. Subsequently, using Starbase v2.0 database, miR-25-3p was confirmed to interact with LINC00858 and was downregulated by LINC00858. Reduction of miR-25-3p expression with an inhibitor significantly attenuated the biological effects of LINC00858 knockdown in CRC cells. Furthermore, using TargetScan, SMAD7 was validated to interact with miR-25-3p and was downregulated by miR-25-3p. Lastly, the ectopic overexpression of SMAD7 rescued the suppressive effects of LINC00858 knockdown in CRC cells. Collectively, the results from the present study, to the best of our knowledge, firstly demonstrated a novel LINC00858/miR-25-3p/SMAD7 regulatory axis that promoted CRC progression, indicating LINC00858 as a promising therapeutic target for CRC.