Abstract: GaN, III-V, SiC and related alloys on Si substrates becomes a hot research area recently. GaN and SiC have wide applications in photonic and electronics, such as high power, high speed devices and LEDs UV detectors etc. Silicon substrates are low cost, available in large diameters and have well characterized electrical and thermal properties. Despite these advantages，silicon has not been popular as a substrate material for GaN, SiC and III-V growth due to several problems mainly related to the thermal and lattice mismatches. Silicon attracted attention as a substrate material for GaN growth when the first MBE grown GaN LED on Si was demonstrated in 1998 from IBM group. Recently. using AlN and AlGaN buffer layers for GaN and SiGe buffer layers for III-V materials growth on Si, the thermal stress and lattice mismatch can be reduced significantly and over 1µm crack free GaN epi-films can be grown on 6 inch Si(111) wafers. High power blue LED on Si have been demonstrated by AZZURRO, in Germany. The power devices on Si also have been made by Nitrinex in USA. The super high power devices on Si are still in instigation. In 2007, UK government set up a solid-state lighting program, which focus on developing GaN based LED on 6 inch Si substrates. On the other hand, continued physical scaling of mainstream silicon CMOS technology has boosted the performance of the Si devices in the past 40 years. Increasing the drive current at low-bias voltage to reduce the gate delay for 30 nm and beyond low-power logic application requires devices possessing channel materials with higher carrier mobility. III-V compounds with mobility as high as 80000 cm²/Vs are possible solutions for Si CMOS beyond 30nm，such as InSb, InAs, and InGaAs. In 2007, DARPA/MTO started a program for compound semiconductors on silicon (COSMOS) focusing on high speed chips embedded in silicon CMOS. The first international symposium deals with “Advances in GaN, GaAs, SiC and related alloy on Si substrates” in MRS 2008 spring meeting will be held on March 24 -28, 2008 in San Francisco, USA.