Indonesia is a natural asphalt producer with the largest deposit in the world known as Asbuton. One of the modified asbuton produced is asphalt Retona Blend 55 production PT. Olah Bumi Mandiri. Asbuton has great potential to be used as a binder on pavement to replace the commonly used oil asphalt. In addition to natural asphalt, coal is also one of the natural wealth in Indonesia which continues to be explored so as to produce waste fly ash that can be used as a filler. The research using Marshall to study the characteristics of the effect of coal fly ash application to HRS-WC mixture with Retona Blend asphalt binder 55 with variation of coal fly ash as a replacement of filler with 0%, 5%, 5,5%, 6% and 6.5%. The test results obtained Marshall characteristics of density values tend to increase, the highest value at 6.5% with a value of 2.23. VMA (Void In Mineral Agregate) tends to decrease the lowest VMA value at 6.5% with a value of 19.21%. VIM (Void In the Mix) tends to have the lowest VIM value at 6.5% with a value of 4.02%. Void (Void Filled Asphalt) has increased, the highest VFA value at 6.5% with a value of 79.09%. Stability in this study has decreased the lowest stability value at 5% with a value of 1502.75 kg. Flow tends to decrease at all levels of coal fly ash at the lowest flow rate at 6.5% with a value of 2.18 mm. MQ (marshall Quotient) tends to increase, the highest MQ value is at 5.5% with a value of 728.07 kg / mm.