why horizontal wind change my vertical speed?
 

When flying I notice the tail wind reduce my VS,if I keep my IAS,which make the descend difficult.But i think only vertical wind change the vertical speed,don't know how does it happen.
It is a stupid question ,thank you very much anyway!

A constant horizontal wind will not change your aerodynamic performance (ias, tas, V/s etc) for a given set of input parameters (power+attitude). I WILL change the angle of your descent relative to the ground, so to descend the same altitude in a given distance, you require a higher V/S.

A CHANGING horizontal wind WILL effect your ROD as it is an example of shear.

Winds usually abate with reducing altitude, so you usually have a reducing tail-wind as you descend. This is an example of a positive shear, and will reduce your V/s for a given power/ IAS.

why horizontal wind change my vertical speed?
 

Oh! You are totally right! I just misunderstand the constant wind and changing wind ! Thank you so much!

It happens (very) occastionaly!! Your welcome and happy flying!