Argent, semée-de-lis, a bend arched Gules.
From a wreath Argent and Gules a sword entwined with a palm frond Proper behind four bamboo spears saltirewise Proper tied with a ribbon Azure behind a bear's face Proper.
The colors, scarlet and white, are those of the Corps of Engineers. The fleurs-de-lis scattered over the shield symbolize the organization's World War II service in Europe, and the curved diagonal band represents outstanding service in the construction of the Canadian-Alaskan Military Highway.
Scarlet and white are the colors traditionally used by Engineer organizations. Red is symbolic of courage, vitality and zeal; white is for integrity. The unit's combat service in Vietnam is emphasized by the bamboo spears which are crossed to show support and strength. The unsheathed sword represents military preparedness and combat service. The palm frond is representative of honor and achievement. The four spears and sword are also indicative of the unit's four Meritorious Unit Commendations and are tied with a blue ribbon acknowledging its Presidential Unit Commendation. The Kodiak bear face surmounts all to signify the battalion's work on the ALCAN Highway, Alaska and Canada, in 1942. The Kodiak is the largest member of the bear family and is found only in Alaska; the unit's distinctive designation is "KODIAK."
The coat of arms was originally approved for the 70th Engineer Combat Battalion on 13 February 1952. It was redesignated for the 70th Engineer Battalion on 2 September 1960. The coat of arms was amended to include a crest on 6 June 1995.