The 23-year-old is in pole position to cap a brilliant rookie season with a maiden European Tour title after finding top gear in the event.
MacIntyre added a bogey-free second round of 65 to his opening 68 at Green Eagle Golf Course in Hamburg to reach 11 under par, four shots clear of Germany’s Bernd Ritthammer, who returned a 66.
Overnight leader Paul Casey struggled to a 73 to lie six shots off the pace alongside Austria’s Matthias Schwab and Italy’s Guido Migliozzi.
MacIntyre’s brilliant debut season has already produced back-to-back runners-up finishes and a tie for sixth in the Open at Royal Portrush, but the 23-year-old from Oban remains intent on improving.
“It’s probably the best I’ve driven the ball this year, it’s not just going straight it’s going miles,” said MacIntyre, who birdied just one of the five par fives on the 7,500-yard layout.
“I don’t know what I’m doing but it’s working so I’m just going to try and continue to do it.
“I can only control what I can control and that’s swinging the golf club for each individual shot so that’s all I’m going to do over the weekend as well and hopefully we can keep the good scores coming.
“I’ve changed quite a few things over the season to improve and they seem to be working. Dave (Burns) my coach is on the bag this week and doing a great job. Off the course when we’re at home we’re practicing the right things and it’s good to see the reward.
“It’s going to be tough, especially when it’s my first time with such a lead. I’m just going to have to learn from this experience.
“I’m doing the right things on the course, doing the right things off the course. I’m nice and relaxed, everything at home’s been brilliant so I’m in the right mindset for going out there this weekend.”
The leader after each round is given the use of one of the sponsor’s cars for the evening and MacIntyre added: “I think Dave was itching to get a wee shot but no, no, it’s my car this time!”
The left-hander is the only Scot through to the weekend after Grant Forrest, Liam Johnston, Richie Ramsay, Duncan Stewart, Marc Warren and David Drysdale all made early exits.
• Gullane’s Marc Owenson finished joint-fourth in the Scottish PGA Championship at Downfield, where Paul O’Hara claimed the title after a play-off victory over 2000 winner Alastair Forsyth.