i added the partical effect to the 3rd solid layer ,what happens is the ramp effect added to solid stops functioning and shows a plain color...can anyone help me out with this and explain why this happens?
We can know nothing. Your description is generic and vague and it is absolutely not clear what you are doing. What particle effect? what layer order? what else? You need to explain a lot better and provide screenshots as well as include all the technical info like which version of AE on what system...
Don't stack those two effects on one solid layer. Create the solid, apply Ramp, Ptrecompose it and THEN apply the particle effect to the precomp, if you so desire.