Hi! I have a problem of interfacing my Nokia 5110 lcd module together with my sd card module. I do some researched on the Internet but I can't find anything useful. I figured out that my Nokia lcd and my sd card module both use SPI interface. My project is about reading a text file (.txt) from the SD card and display it on the Nokia 5110 lcd module. Is this type of thing possible? Thanks 
As long as only the SPI pins are shared (and the SD card uses a different pin for CS than the screen)
Depending on the board you're using, and the size of the text file, you might have to read it in chunks to fit it into memory.
There should be no problem with this, but try sending the text to serial monitor instead/as well, thereby getting a better idea of what is going on. Your problem may merely be one of formatting. As far as I know, the 5110 always runs on software SPI and doesn't care what pins it uses, so long as they are properly specified in the library, and the CS is unique to it, as mentioned above.