.....Here, a new surface enhanced Raman scattering (SERS) based protocol using telomeric elongation controlled SERS (TEC-SERS) effect for the ultrasensitive telomerase detection is presented. The TEC-SERS protocol not only provides an unprecedented high sensitivity but also avoids laborious PCR procedures. The detection limit is ≈2-3 orders of magnitude lower than those of previously reported methods. This highly sensitive and straightforward TEC-SERS protocol can be developed as a routine telomerase detection method, which would greatly facilitate the telomerase based ultra-early diagnosis of malignant tumors and the fast screening of anti-cancer drugs.