AIM:To discuss the clinical effects of congenital nasolacrimal duct obstruction(CNLDO) in different stages with conservative treatment and lacrimal passage probing. METHODS:Thirty-seven infants (41 eyes), aged 20 days to 2 months, diagnosed with CNLDO were followed in the study between 2008 and 2011. Conservative dacryocyst massage was performed on infants ＜6 months. Lacrimal passage probing was performed on infants ＞6 months when conservative treatment had no effect. RESULTS:All infants finished follow-up,25 eyes(61.0%) were cured within six months after birth. The rest of 16 eyes(39.0%) received lacrimal passage probing after six months, of which 14 eyes resolved after the first probing and 2 eyes resolved after the second probing. CONCLUSION:Conservative treatment before 6 months in CNLDO was recommended. After 6 months, lacrimal passage probing could help promote the effect. 