want to send ADC 0804 8 bit parallel data through RF communication

if i have 8 bit data output from the adc 0804 ic. what should i interface it with before sending the data to RF transmitter?

You need a Encoder IC like HT-12E to make it serial. and connect the transmitter circuit on the out pin of HT-12E. You can refer a lot of circuits available in internet using HT-12E & HT-12D(Decoder at receiver end)

can I connect ADC data directly to HT 12E ? Is there a need of microcontroller in between ?

Without micro controller also you can send the data by connecting the ADC output directly to parallel input pins of HT-12E. But for sending the data out from the ADC 0804, you need a microcontroller or some intelligence to issue the control signals (tell me if i am wrong).